diff options
Diffstat (limited to 'drivers/ata/libata-core.c')
| -rw-r--r-- | drivers/ata/libata-core.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 9467c2f6019..b666f51da7e 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -4346,6 +4346,36 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc) } /** + * ata_std_qc_defer - Check whether a qc needs to be deferred + * @qc: ATA command in question + * + * Non-NCQ commands cannot run with any other command, NCQ or + * not. As upper layer only knows the queue depth, we are + * responsible for maintaining exclusion. This function checks + * whether a new command @qc can be issued. + * + * LOCKING: + * spin_lock_irqsave(host lock) + * + * RETURNS: + * ATA_DEFER_* if deferring is needed, 0 otherwise. + */ +int ata_std_qc_defer(struct ata_queued_cmd *qc) +{ + struct ata_link *link = qc->dev->link; + + if (qc->tf.protocol == ATA_PROT_NCQ) { + if (!ata_tag_valid(link->active_tag)) + return 0; + } else { + if (!ata_tag_valid(link->active_tag) && !link->sactive) + return 0; + } + + return ATA_DEFER_LINK; +} + +/** * ata_qc_prep - Prepare taskfile for submission * @qc: Metadata associated with taskfile to be prepared * @@ -7111,6 +7141,7 @@ EXPORT_SYMBOL_GPL(ata_interrupt); EXPORT_SYMBOL_GPL(ata_do_set_mode); EXPORT_SYMBOL_GPL(ata_data_xfer); EXPORT_SYMBOL_GPL(ata_data_xfer_noirq); +EXPORT_SYMBOL_GPL(ata_std_qc_defer); EXPORT_SYMBOL_GPL(ata_qc_prep); EXPORT_SYMBOL_GPL(ata_dumb_qc_prep); EXPORT_SYMBOL_GPL(ata_noop_qc_prep); |